My personal opinion: Cartmans' brother is the Genetic Engineers'
"friend Kevin". In fact, they were Siamese twins, separated at birth
(explaining the scar on Cartmans' back).
We'll know more when "Kevin" speaks.
I also think that Cartman/Kevin were created by a "DNA cocktail"
created by the Engineer.
Or else it's that whole alien thing.
Who knows. A legitimate cliff-hanger.Thanks, Dave